Don't think there are too many "pros" with wheeling a hardtop, especially if you have a good heater. I can think of several "cons" and most of them were mentioned by Oliver.
It is all up to you though. I say try it out, and see how you like it.
I plan to keep mine on for most wheeling, and just remove the doors and rear hatch.
Can you post some pics of your '5 with the hardtop? Especially wheeling pics. We could use some new pics in your Acme pic thread...I don't recall you posting any pics of your own rig there!
Here is a pic of a '5 that I have found with an Acme top doing some mild trail riding.